I have three indoor plastic flower pots with airplane plants in them and today I noticed that they had some sort of white fuzzy mold or fungus on the soil. Does this mean that I might be over watering them? And can this be fixed or will it kill the plant?
Sounds like mealy bug or just plain mold of some kind. You should allow the top layer of soil to dry between waterings. What are airplane plants?? You need to also keep the plants in a well aired place (no A/C or heaters close by though) and no direct fan blowing. Find a houseplant fungicide at any garden center or even hardware store and follow the label directions.
It's probably some harmless mold. I had something, maybe the same thing, like that last spring when I had some seedlings inside, waiting for last frost to put them outside. It was just a case of potting soil being damp for awhile, but it didn't hurt the plants. Allow the top of the soil (1/2 inch, maybe more; I don't know what size pot or type of plant -- is airplane plant same as spider plant?) to dry between waterings, and you shouldn't have problems -- it will dry out and be more grey & dead than white & fuzzy. If you really want to get rid of it (for aesthetic reasons, or to help to water appropriately -- I seem to remember that after awhile it was sort of hydrophobic, and the water would only absorb along the edges), then let the soil get quite dry (if the plant can take it; a spider plant could), scape off the surface well, top-dress it with fresh potting soil (not the kind with fertilizer, which could encourage mold to return), and water it lighter than you usually would at first -- just enough to re-wet all the soil, but not anywhere near saturation. Then water as normal -- let the top portion of the soil get dry, then give a thorough watering.